1. Field of the Invention
The present invention relates to a method for manufacturing an electrophoretic display element capable of realizing high-definition color display.
2. Description of the Related Art
In recent years, many electrophoretic display elements using microcapsules have been proposed. Examples thereof include, for example, an electrophoretic display element composed of microcapsules, each enclosing electrophoretic particles and a suspension with a color tone different from that of the electrophoretic particles (Japanese Patent Laid-Open No. 64-86116) and an electrophoretic display element composed of microcapsules, each enclosing two types of electrophoretic particles different in the color tone and the polarity and a clear, colorless suspension (Japanese Patent Laid-Open No. 11-119264). Conventionally, such a microcapsule for electrophoretic display is prepared primarily by any one of an interfacial polymerization method, an in situ polymerization method and a phase separation method (a coacervation method), the microcapsule is mixed with a binder resin, the resulting resin composition is applied on an electrode substrate by using a roll coater method, a roll laminator method, a screen printing method, a spray method and the like, and therefore, an electrophoretic display element is prepared. This has been a general manufacturing method.
However, when high-definition display was intended, there was a problem in that the microcapsules had to be precisely arranged on the electrode constituting display pixels, and the microcapsules had to be driven and be controlled independently.
When color display was intended, there was also a problem in that uniform microcapsules of different display colors had to be arranged in predetermined locations on the electrode substrate on a pixel basis, and each of these microcapsules had to be driven and be controlled independently.
Conventional microcapsules for electrophoretic display elements were prepared primarily by an interfacial polymerization method, an in situ polymerization method, a phase separation method (a coacervation method) and the like. In general, microcapsules prepared by these methods had broad particle size distributions, and in order to prepare microcapsules having desired particle diameters, classification operation had to be performed by a screening method, a gravity separation method and the like. Consequently, it was difficult to prepare uniform microcapsules by conventional manufacturing methods.
Furthermore, it was impossible to precisely arrange microcapsules in predetermined locations on an electrode substrate by mixing microcapsules with a binder resin, and applying the resulting resin composition on an electrode substrate by using a roll coater method, a roll laminator method, a screen printing method, a spray method and the like.